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Indexed by:期刊论文

Date of Publication:2014-10-01

Journal:CHINESE JOURNAL OF CHEMISTRY

Included Journals:SCIE、Scopus

Volume:32

Issue:10,SI

Page Number:985-990

ISSN No.:1001-604X

Key Words:emulsion catalysis; asymmetric catalysis; organocatalysis

Abstract:A series of of amphiphilic imidazole based secondary and primary amine catalysts were synthesized and shown to be very effective with an acid cocatalyst for the asymmetric reaction of cyclohexanone to ,-unsaturated -keto ester. Interestingly, primary and secondary amine catalysts show different regio-selectivities in this reaction. Under the catalysis of secondary amine 1, excellent enantioselectivities were observed for the products from direct 3+3 reactions of cyclohexanone with ,-unsaturated -keto esters using water as the solvent. Moreover, the same reactants catalyzed by the primary amines 2 lead to the aldol reactions, affording the corresponding products with high diastereoselectivities and up to 97% ee. Theoretical studies on the transition states by using a model in gas phase revealed that steric effect plays an important role on different chemo-selective induction between the secondary amine 1 and primary amine 2.